The sale took place in three tranches on March 6, 7 and 10, coming on the heels of a 20-percent market rally on March 5 that traders said had been triggered by speculation the investor, a cash-strapped charitable foundation, was selling down its bank holdings.

Earlier on Monday, the Aleotti family, Monte dei Paschi's second-largest investor, said it had slashed on March 5 its 4 percent stake to around 1 percent.